A baby girl who was born with HIV has been cured after very early treatment with standard drug therapy, US researchers have said, in a potentially ground-breaking case that could offer insights on how to eradicate HIV infection in its youngest victims.

The child's story is the first account of an infant achieving a so-called functional cure, a rare event in which a person achieves remission without the need for drugs and standard blood tests show no signs that the virus is making copies of itself.

More testing needs to be done to see if the treatment would have the same effect on other children, but the results could change the way high-risk babies are treated and possibly lead to a cure for children with HIV, the virus that causes AIDS.

"This is a proof of concept that HIV can be potentially curable in infants," said Dr Deborah Persaud, a virologist at Johns Hopkins University in Baltimore, who presented the findings at the Conference on Retroviruses and Opportunistic Infections in Atlanta.

The child's story differs from the now famous case of Timothy Ray Brown, the so–called "Berlin patient," whose HIV infection was completely eradicated through an elaborate treatment for leukemia in 2007 that involved the destruction of his immune system and a stem cell transplant from a donor with a rare genetic mutation that resists HIV infection.

Instead of Brown's costly treatment, the Mississippi baby's case involved the use of a cocktail of widely available drugs already used to treat HIV infection in infants.

When the baby girl was born in a rural hospital, her mother had just tested positive for HIV infection. Because her mother had not received any prenatal HIV treatment, doctors knew the child was born at high risk of being infected. So they transferred the baby to the University of Mississippi Medical Center in Jackson, where she came under the care of Dr Hannah Gay, a pediatric HIV specialist.

Because of her high infection risk, Dr Gay put the infant on a cocktail of three standard HIV-fighting drugs when she was just 30 hours old, even before lab tests came back confirming her infection. In more typical pregnancies when an HIV-infected mother has been given drugs to reduce the risk of transmission to her child, the baby would only have been given a single drug to reduce her infection risk.

Researchers believe this early use of antiviral treatment likely resulted in the infant's cure by keeping the virus from forming hard-to-treat pools of cells known as viral reservoirs, which lie dormant and out of the reach of standard medications. These reservoirs rekindle HIV infection in patients who s– therapy, and they are the reason most HIV-infected individuals need lifelong treatment to keep the infection at bay.

After starting on treatment, the baby's immune system responded and tests showed levels of the virus were diminishing until it was undetectable 29 days after birth.